U.S. patent number 8,901,801 [Application Number 13/150,432] was granted by the patent office on 2014-12-02 for multiple electrode plane wave generator.
This patent grant is currently assigned to Qualcomm Incorporated. The grantee listed for this patent is Jack C. Kitchens, John K. Schneider. Invention is credited to Jack C. Kitchens, John K. Schneider.
United States Patent |
8,901,801 |
Schneider , et al. |
December 2, 2014 |
Multiple electrode plane wave generator
Abstract
The invention may be embodied as an ultrasonic plane wave
generator having a first sheet of piezoelectric material and a
second sheet of piezoelectric material. A shared electrode may be
between the first sheet and the second sheet. A first electrode set
may have a plurality of electrodes, and these electrodes may be
positioned with respect to the first sheet to form a set of wave
generators. A wave generator in this first wave generator set may
include the shared electrode, the first sheet, and one of the
electrodes in the first electrode set. A second electrode set may
have a plurality of electrodes, and these electrodes may be
positioned with respect to the second sheet to form another set of
wave generators. A wave generator in this second wave generator set
may include the shared electrode, the second sheet, and one of the
electrodes in the second electrode set.
Inventors: |
Schneider; John K. (Snyder,
NY), Kitchens; Jack C. (Tonawanda, NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
Schneider; John K.
Kitchens; Jack C. |
Snyder
Tonawanda |
NY
NY |
US
US |
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|
Assignee: |
Qualcomm Incorporated (San
Diego, CA)
|
Family
ID: |
45021505 |
Appl.
No.: |
13/150,432 |
Filed: |
June 1, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20110291531 A1 |
Dec 1, 2011 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61350248 |
Jun 1, 2010 |
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Current U.S.
Class: |
310/334; 310/339;
310/335; 310/337 |
Current CPC
Class: |
B06B
1/0611 (20130101) |
Current International
Class: |
H01L
41/08 (20060101) |
Field of
Search: |
;310/334,335,336,337,327,365-367,800 ;73/803 ;348/61
;382/124,125 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
International Search Report and Written Opinion from the
International Searching Authority for PCT/US2011/038687, Sep. 12,
2011, Ultra-Scan Corporation. cited by applicant.
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Primary Examiner: Dougherty; Thomas
Assistant Examiner: Addison; Karen B
Attorney, Agent or Firm: Hodgson Russ LLP
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of priority to U.S. provisional
patent application Ser. No. 61/350,248, filed on Jun. 1, 2010,
which is incorporated herein by reference in its entirety.
Claims
What is claimed is:
1. An ultrasonic plane wave generator comprising: a first sheet of
piezoelectric material and a second sheet of piezoelectric
material; a shared electrode between the first sheet and the second
sheet; a first electrode set having a plurality of electrodes
positioned with respect to the first sheet to form a first
ultrasonic plane wave generator set, wherein an ultrasonic plane
wave generator in the first ultrasonic plane wave generator set
includes the shared electrode, the first sheet, and one of the
electrodes in the first electrode set; and a second electrode set
having a plurality of electrodes positioned with respect to the
second sheet to form a second ultrasonic plane wave generator set,
wherein an ultrasonic plane wave generator in the second ultrasonic
plane wave generator set includes the shared electrode, the second
sheet, and one of the electrodes in the second electrode set.
2. The ultrasonic plane wave generator of claim 1, wherein adjacent
electrodes of the first electrode set are separated from each
other.
3. The ultrasonic plane wave generator of claim 2, wherein adjacent
electrodes of the second electrode set are separated from each
other.
4. The ultrasonic plane wave generator of claim 1, wherein each
electrode in the first electrode set has one or more surface
normals which define a surface of that electrode, and each
electrode in the second electrode set has one or more surface
normals which define a surface of that electrode; and wherein a
subset of electrodes in the first electrode set are positioned
relative to the electrodes in the second electrode set so that
surface normals of the subset of electrodes in the first electrode
set are not coincident with surface normals of the electrodes in
the second electrode set.
5. The ultrasonic plane wave generator of claim 1, wherein each
electrode in the first electrode set has one or more surface
normals which define a surface of that electrode, and each
electrode in the second electrode set has one or more surface
normals which define a surface of that electrode; and wherein
electrodes in the first electrode set are positioned relative to
electrodes of the second electrode set to provide overlapping areas
in which surface normals of electrodes in the first electrode set
are coincident with surface normals of electrodes in the second
electrode set.
6. The ultrasonic plane wave generator of claim 5, wherein surface
normals corresponding to an edge portion of electrodes in the first
electrode set are coincident with surface normals corresponding to
an edge portion of electrodes in the second electrode set.
7. The ultrasonic plane wave generator of claim 6, wherein each
electrode of the first electrode set has a surface area, and each
electrode of the second electrode set has a surface area, wherein
the overlapping areas are less than 2% of the surface area of the
first electrode set.
8. The ultrasonic plane wave generator of claim 7, wherein the
overlapping areas are less than 2% of the surface area of the
second electrode set.
9. The ultrasonic plane wave generator of claim 1, further
comprising a platen covering at least one of the first electrode
set or the second electrode set.
10. The ultrasonic plane wave generator of claim 9, wherein the
platen is polystyrene.
11. The ultrasonic plane wave generator of claim 9, wherein the
platen is polymethylmethacrylate.
12. The ultrasonic plane wave generator of claim 9, wherein the
platen is a material having the ability to conduct ultrasound.
13. The ultrasonic plane wave generator of claim 1, wherein the
piezoelectric material is polyvinylidene fluoride.
14. The ultrasonic plane wave generator of claim 1, wherein the
piezoelectric material is polyvinylidene fluoride
trifluoroethylene.
15. The ultrasonic plane wave generator of claim 1, wherein the
piezoelectric material is a lead zirconium titanate ceramic.
16. The ultrasonic plane wave generator of claim 1, wherein the
piezoelectric material is a lead metaniobate ceramic.
17. The ultrasonic plane wave generator of claim 1, wherein at
least one of the wave generators in the first ultrasonic plane wave
generator set is individually activatable.
18. The ultrasonic plane wave generator of claim 17, wherein at
least one of the wave generators in the second ultrasonic plane
wave generator set is individually activatable.
19. The ultrasonic plane wave generator of claim 17, further
comprising a computer in communication with the ultrasonic plane
wave generators of the first ultrasonic plane wave generator set
for receiving information from the ultrasonic plane wave generators
of the first ultrasonic plane wave generator set.
Description
FIELD PF THE INVENTION
The present invention relates to an ultrasonic wave generator, and
specifically to a reflex ultrasonic imaging system having a
plurality of individual wave generators.
BACKGROUND OF THE INVENTION
Some existing reflex ultrasonic imaging systems make use of a
pulse-generating system that has a plane wave generator. A prior
art embodiment of a plane wave generator 9 is shown schematically
in FIGS. 1A and 1B. FIG. 1A depicts components of the plane wave
generator 9. There it is shown a sheet of piezoelectric material 2
positioned between an upper electrode 1 and a lower electrode 3.
The plane wave generator 9 produces a longitudinal wave that
insonifies an object that is in contact with an imaging platen. By
detecting the energy reflected by the object, information about the
object may be obtained. The information may be processed by a
computer to provide a visual representation of the object via a
monitor.
Piezoelectric devices can be used as plane wave generators, and
they typically include piezoelectric ceramics, piezoelectric
crystals or piezoelectric polymers. To an electronic system that
supplies power to the plane wave generator, the plane wave
generator looks like a low impedance electrical load. The driving
circuits required for such low impedance loads must deliver more
power than the driving circuits for high impedance devices.
SUMMARY OF THE INVENTION
The invention may be embodied as an ultrasonic plane wave generator
having a first sheet of piezoelectric material and a second sheet
of piezoelectric material. A shared electrode may be between the
first sheet and the second sheet. A first electrode set may have a
plurality of electrodes, and these electrodes may be positioned
with respect to the first sheet to form a set of wave generators. A
wave generator in this first wave generator set may include the
shared electrode, the first sheet, and one of the electrodes in the
first electrode set. A second electrode set may have a plurality of
electrodes, and these electrodes may be positioned with respect to
the second sheet to form another set of wave generators. A wave
generator in this second wave generator set may include the shared
electrode, the second sheet, and one of the electrodes in the
second electrode set.
Adjacent electrodes of the first electrode set may be separated
from each other. Adjacent electrodes of the second electrode set
may be separated from each other. In such an embodiment of the
invention, in order to insonify an object that is being imaged, the
electrodes of the second electrode set may be positioned so as to
emit energy toward an object so that the energy travels primarily
through the gaps between the electrodes of the first electrode
set.
Each electrode in the first electrode set may have one or more
surface normals which define a surface of that electrode, and each
electrode in the second electrode set may have one or more surface
normals which define a surface of that electrode. In one embodiment
of the invention, electrodes in the first electrode set may be
positioned relative to the electrodes in the second electrode set
so that surface normals of the subset of electrodes in the first
electrode set are not coincident with surface normals of the
electrodes in the second electrode set. In such an arrangement, the
electrodes are said to be non-overlapping. In another embodiment,
electrodes in the first electrode set may be positioned relative to
electrodes of the second electrode set to provide overlapping areas
in which surface normals of electrodes in the first electrode set
are coincident with surface normals of electrodes in the second
electrode set.
At least one of the wave generators in the first wave generator set
may be individually activatable. Additionally, at least one of the
wave generators in the second wave generator set may be
individually activatable. In this manner, some of the wave
generators can be activated while others of the wave generators are
not activated.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the nature and objects of the
invention, reference should be made to the accompanying drawings
and the subsequent description. Briefly, the drawings are:
FIG. 1A is an exploded schematic view of a prior art ultrasonic
plane wave generator with a piezoelectric material between two
electrodes;
FIG. 1B shows the unexploded view of the device depicted in FIG.
1A;
FIG. 2A is an exploded schematic view of an ultrasonic plane wave
generator that is in keeping with the invention;
FIG. 2B shows an unexploded view of the device depicted in FIG.
2A;
FIG. 2C depicts electrodes arranged according to the invention in
which there are overlapping portions;
FIG. 2D depicts electrodes arranged according to the invention so
as not to have an overlapping portion;
FIG. 2E is a perspective view of the electrode arrangement depicted
in FIG. 2C;
FIG. 3A is a top view showing electrodes arranged according to the
invention in which there are overlapping portions;
FIG. 3B is an exploded partial perspective view of a device that is
in keeping with the invention;
FIG. 3C is a side view showing the device of FIG. 3B in unexploded
form; and.
FIG. 4 is a flow chart of a method that is in keeping with the
invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 2A and 2B depict an embodiment of the invention. In FIGS. 2A
and 2B, there is a multiple electrode plane wave generator 10,
which may be constructed by sandwiching a thin continuous electrode
6 between two sheets of piezoelectric material 5, 7. A first
electrode set 4 may have a plurality of electrodes 4a, and these
electrodes may be positioned with respect to a first sheet of
piezoelectric material 5 to form a set of wave generators. A wave
generator in this first wave generator set includes the continuous
electrode 6, the first sheet 5, and one of the electrodes in the
first electrode set 4a. A second electrode set 8 may have a
plurality of electrodes 8a, and these electrodes may be positioned
with respect to the second sheet 7 to form another set of wave
generators. A wave generator in this second wave generator set
includes the shared electrode 6, the second sheet 7, and one of the
electrodes in the second electrode set 8a. Each wave generator in
the first or second generator set may be individually
activatable.
FIG. 2A depicts an exemplary embodiment of the invention where the
first set of electrodes 4 is applied to the first sheet of
piezoelectric material 5, the second set of electrodes 8 is applied
to the second sheet of piezoelectric material 7, and the continuous
electrode 6 is applied between the first sheet 5 and second sheet
7. However, the sheets 5, 7 do not necessarily need to be applied
directly to the first set 4, second set 8, or continuous electrode
6.
Each electrode 4a of the first electrode set 4 may be separated
from adjacent electrodes 4a in the first set. In doing so, a gap 11
is created between adjacent electrodes 4a. Similarly, each
electrode 8a of the second electrode set 8 may be separated from
adjacent electrodes 8a in the second set. In doing so, a gap 11 is
created between adjacent electrodes 8a. FIG. 3C illustrates that
the electrodes 4a in the first set of electrodes 4 may be staggered
relative to the electrodes 8a in the second set of electrodes 8. In
such an arrangement, the electrodes 8a are positioned to emit
energy (represented by rays 13 that travels through the gaps 11
between the electrodes 4a. As such, an object that is being imaged
will be insonified more completely than if only the electrodes 4a
existed. In doing so, a more complete image of the object may be
generated.
FIGS. 2C-2E depict exemplary electrode arrangements according to
the present invention. Piezoelectric materials 5, 7 and continuous
electrode 6 are omitted from FIGS. 2C-2E for ease of illustration.
The orientation of electrodes 4a with respect to electrodes 8a will
be discussed with reference to surface normals 12, which are
vectors that are perpendicular to a flat surface, or vectors that
are perpendicular to a tangent plane with respect to a particular
point on a curved surface. As can be seen in FIGS. 2C-2E, the
surface normals 12 which define the surface of the electrodes 8a
and which also extend through the continuous electrode 6 (not
shown) may be arranged in various ways with respect to the surface
normals 12 which define the surface of the electrodes 4a and also
extend through the continuous electrode. For example, in FIGS. 2C
and 2E some of the surface normals 12 of the electrode 8a are not
coincident with surface normals which extend from the electrode 4a.
In these areas, the electrodes 4a, 8a are not overlapping. In those
areas where electrode 4a overlaps with electrode 8a, surface
normals of electrode 8a are coincident with surface normals of
electrode 4a. Thus, there may be non-coincident normals 12a and/or
coincident normals 12b. With respect to those surface normals
extending through electrode 6, in the "overlapping" areas 14 (two
of which are called out in FIG. 3a), the surface normals of an
electrode 8a may be coincident and parallel with surface normals of
an electrode 4a. The "overlapping" areas 14 may correspond to an
edge portion of the electrodes 4a, 8a. The electrodes 4a, 8a may
"overlap" slightly to assure that a complete image of the object
can be obtained from the information provided by the generator 10.
In one particular embodiment, the "overlapping" areas will be less
than 2% of the total surface area of an electrode 4a, 8a.
An alternative arrangement is shown in FIG. 2D, in which there are
no overlapping areas. FIG. 2D shows an electrode 4a which does not
overlap with the electrode 8a. Here, the electrode 4a and electrode
8a are arranged so that the surface normals 12 are not
coincident.
Each electrode 4a, 8a may be thought of as being part of a small
plane wave generator ("SPWG"). A SPWG is comprised of a single
electrode 4a or 8a, the large common electrode 6, and the
piezoelectric material 5 or 7 that is between. In use, less than
all of the SPWGs of the plane wave generator 10 may be activated at
any particular time. For example, to keep the power requirement for
a particular time period low, only one SPWG is activated at any
particular time during the capture of information, and later, that
information can be used to create an image of the object. If the
object extends beyond a single electrode 4a or 8a, the information
derived from each SPWG may be sent to a computer that is programmed
to combine the information and provide an image of the object via a
monitor.
The present invention may act as a plurality of small plane wave
generators ("SPWG") that are each addressable. Insonification of an
object to be imaged can be performed in segments corresponding to
each SPWG in order to take advantage of the lower power
requirements of the individual SPWG. Information may be gathered
using each segment, and the gathered information may be used to
create an image of the object.
The amount of electrical power applied to a single SPWG is less
than the power required to activate a full area plane wave
generator having the ability to insonify a similar overall area.
Consequently, by using a plane wave generator 10 that is in keeping
with the invention, the peak power requirement that must be met by
the driving circuit may be lower, and the physical size of the
driving circuit can be smaller. Specifically, by individually
activating individual SPWGs one at a time, the peak power
requirement is limited to the power necessary to power each SPWG.
This may result in lower peak power requirements because peak power
requirements for each SPWG are lower than a prior art plane wave
generator 9. The present invention may also allow a larger area
insonification device to be used in a system that has a small
battery, for example in a portable device such as a personal
digital assistant.
Each SPWG may be excited independently from the other SPWGs and at
different times. In doing so, the electrical driver circuit used to
activate the SPWGs may (a) have a lower peak power requirement, (b)
be physically smaller, (c) be less expensive, and (d) be more
reliable. With regard to being more reliable, it is normally the
case that fewer parts provide a more reliable system. However, in
this situation a different result is expected. It is believed that
the lower power requirements of the present invention result not
only in an ability to use components that are better able to
withstand and handle the power needed to generate an image, but the
temperature of some components is reduced as well, and it is
believed this will result in higher reliability.
FIG. 4 depicts a method of insonifying an object using a multiple
electrode plane wave generator 10 according to the present
invention. A first sheet of piezoelectric material and a second
sheet of piezoelectric material may be provided 110. A shared
electrode may be placed 120 between the first sheet and the second
sheet. A first electrode set may be provided 130 having a plurality
of electrodes positioned with respect to the first sheet to form a
set of wave generators. A wave generator in the first wave
generator set includes the shared electrode, the first sheet, and
one of the electrodes in the first electrode set. A second
electrode set may be provided 140 having a plurality of electrodes
positioned with respect to the second sheet to form a second set of
wave generators. A wave generator in the second wave generator set
includes the shared electrode, the second sheet, and one of the
electrodes in the second electrode set. A wave generator in the
first wave generator set may be activated 150 at a first time and a
first set of information may be obtained. A wave generator in the
second wave generator set may be activated 160 at a second time and
a second set of information may be obtained. Then a different one
of the wave generators of the first wave generator set may be
activated, followed by a different one of the wave generators of
the second wave generator set may be activated. This process may be
continued until all wave generators have been activated, and
information about the object has been obtained as a result of
energy emitted from each of the wave generators.
Although the present invention has been described with respect to
one or more particular embodiments, it will be understood that
other embodiments of the present invention may be made without
departing from the spirit and scope of the present invention.
Hence, the present invention is deemed limited only by the appended
claims and the reasonable interpretation thereof.
* * * * *